. "Examples of the repeating unit having a group represented by any of the general formulae (VIIa) to (VIId) include those wherein at least one of R13??? to R16??? in the above general formula (II-AB1) or (II-AB2) has a group represented by any one of the general formulae (VIIa) to (VIId) (for example, a group ???COOR5 wherein R5 is a group represented by any of the general formulae (VIIa) to (VIId))" . . .